Car roof



G. G. GILPN CAR n-oQF Nov. '21) 1933.

Filed Aug. `19, 19:52 -2 sheets-sheet 2 Patched Nov., 21, 1933 UNITED,STATES CAR ROOF Garth G. Gilpin, Riverside, Ill., assigner to P. H.

Murphy Company, New Kensington, Pa., a corporation of PennsylvaniaApplication August 19, 1932. Serial N0. 629,419

9 Claims. (Cl. 10S-'5.4)

My invention relates to all metal car roofs. The principal object is todevise a design of roof sheet which is easy to manufacture, is welladapted for use in car roofs and'contributes resiliency to the roof. Itconsists principally in a roof sheet formed with a raised H-shaped ribdisposed longitudinally of. the sheet at or near the middle thereof anddecreasing in depth from the ridge towards the eaves.' It also consistsin the parts and combinations of parts hereinafter described andclaimed.

In the accompanying drawings, wherein like symbols refer to like partswherever they occur,

Fig. 1 is a plan view of a portion of a. car roof embodying myinvention; y

Fig. 2 is a partial cross-section thereof on the line 2-2 of Fig. 1;

Fig. 3 is a partial cross-section thereof on the line 3-3 of Fig. 1;

Fig. 4 is a partial longitudinal section along the ridge as indicated bythe line 4 4 of Fig. 1; and

Figs. 5 and 6 are partial longitudinal sections on the lines 5-5 and 6 6respectiveLv, oi Fig. 1.

'Ihe sheets 1 of the present construction span the distance between sideplates 2 and have their ends turned down over and against the sideplates, to which they are riveted by horizontal rivets 3, the sheetsbeing preferably pitched. Adjacent sheets have upstanding flanges 4along their side margins which flanges are straddled by invertedU-shaped seam caps or covers 5, said flanges and caps being rivetedtogether by horizontalrivets. Preferably, the sidemarginal portions ofthe sheets are formed into panels 7 raised slightly above the adjacentportions of the roof sheets, which portions are herein considered as atthe general level of the sheet.

Disposed longitudinally of each sheet at or near the middle thereof is araised rib 4 which is of considerable depth at the vridge but whichdecreases in depth toward the eaves and preferably merges into thegeneral level of the sheet above the side plates, the decrease in depthbeing quite gradual except at the end portions, where the decrease issomewhat more abrupt. The surface of the top 8 of this rib issubstantially fiat from the ridge to each end of the rib. The portion 9of the rib at or near the ridge is preferably of a width substantiallyequal to half the distance between adjacent roof seams.

Each end of said rib A is bifurcated or divided into two parallelbranches 10 whose outer sides or walls 11 are continuous with the sidesor walls oftherids! portionof theribA. Saidbranches are separated by anintervening `flat bottomed depression 12 which extends longitudinally ofthe rib and is preferably of about the same width as either of suchbranches. At the outer end of said depression, its bottom is at thegeneral level of the sheets; and from this level said bottom incline'supwardly and inwardly and merges into the top of the rib at a distancefrom the ridge approximately equal to one-fourth of the distance betweenthe ridge and the side plate. Thus e5 said rib is H-shaped in plan view.In longitudinal section at and near the ridge, the metal of the top ofthe rib is continuous the full width of the rib; whereas, inlongitudinalI section through the end portions of the rib, the overallwidth of this rib remains substantially the same but there is a gapbetween the two stretches of metal constituting thetops of the branchesof said rib. Whenvsheets with such H-shaped ribs are used in connectionwith standing seam constructions, they add nothing to the overallthickness of the roof, as the ribs need not be higher than such seams.

The operation of a roof with my H-shaped ribs' may be explainedv bycomparison with similar roofs wherein the tops of the ribs arecontinuous from side to side throughout the length of the rib. In bothcases, the rib functions after the manner of a beam, that is, the metalin the top of the rib acts in compression and the metal in the bottomsof the channel acts in tension. As the compressive stress in 'a beam isa maximum midway between its ends and gradually decreases towards itsends, it is obvious that, for equal carrying strength, less metal isrequired in the vtop of the rib near the ends thereof than is requirednear the middle thereof. It is also obvious that if there is enoughmetal in the top of a plain or non-bifurcated rib in and near the ridgefor proper beam action, then thereis more metal in the top of the endportion of said rib than is required for the strength of the rib. On theother hand, lessening the amount of the metal towards the ends of therib decreases the stiffness of the ribs. In conformity with these prin-100 Vciples, applicants H-shaped rib has a great load carrying capacitydue to the metal-being continuous from side to side of the ribthroughout its ridge region wherein the compression stress is greatest;and still it has a sufilcient degree of 105 -resiliency, without beingspringy, due to the bifurcation of the rib and the consequent decreasein the amount of metal in the top thereof in the neighborhood of theends and the concomitant formation of additional vertical web 1 10`members. Thus. as the bifurcation begins beyond the region of maximumcompression stress, the load carrying capacity of the rib is notdecreased, while the gradual depression of the middle portion of theends of the ribs makes it feasible to obtain the desired resiliencywithout undue springiness. Consequently, the roof is not only light,thin and strong but is well adapted to.

yield resiliently to stresses which might disrupt a rigid roof and hasthe special merit of cushioning the roof againsty such shocks as areoccasioned by low joints in the railway track and the like.

What I claim is:

1. A car roof sheet comprising a substantially flat-topped raisedH-shaped rib disposed lengthwise thereof, the portions between thebranches of the H being substantially flat and of uniform width andrising from the plane of the sheet at their eaves ends to the plane ofthe top of the rib at their ridge ends.

2. A car roof sheet comprising a substantially flat-topped raisedH-shaped rib disposed lengthwise thereof, said rib being located nearthe middle of the sheet and being approximately one-half as' wide assaid sheet, the portions between the branches of the H beingsubstantially fiat-and of uniform width and rising from the plane of thesheet at their eaves ends to the plane of the top of the rib at theirridge ends.

3. A car roof sheet comprising a substantially nat-topped raisedH-shaped rib disposed longitudinally of the sheet in the middle thereof,said rib decreasing in depth from the ridge towards the eaves with itsends merging into the plane of the sheet short of the ends of saidsheet, the portions between the branches of the H being substantiallyflat and of uniform width and .rising from the plane of the sheet attheir eaves ends to the plane of the top of the rib at their ridge ends.

4. A car roof comprising side plates, roof sheets with their endssecured thereto and with upstand- 4ing side flanges capped and securedtogether by horizontal rivets, each roof sheet comprising a raisedH-shaped rib disposed lengthwise of the sheet near the middle thereofand extending beyond the inner edges. of theside plates.

5. A car roof comprising roof sheets with up.- standing side flangescapped and secured together by horizontal rivets, each roof sheetcomprisingA a substantially flat-topped raised H- shaped rib disposedlengthwise of the sheet near the middle thereof and being approximatelyonehalf as Wide as `said sheet, the portions between the branches of theH being substantially flat and of uniform width and rising from theplane of the sheet at their eaves ends to the plane of the top of therib at their ridge ends.

6. A car roof comprising roof sheets with upstanding side flanges cappedand secured together by horizontal rivets, each roof sheet comprising asubstantially fiat-topped raised H- shaped rib disposed longitudinallyof the sheet in the middle thereof, said rib decreasing in depth fromthe ridge towards the eaves with its ends merging into the plane of thesheet beyond the inner edges of the side plates.

7. A car roof comprising roof sheets having upstanding flanges alongtheir side margins rig-n idly secured together, each sheet having asubstantially flat-topped raised H-shaped rib along its longitudinalmiddle portion, the cross-sectional area of said rib in the neighborhoodof the ridge being substantially equal to the sum of thecross-sectional'areas of the lower side portions of said sheet.

8. A car roof comprising roof sheets whose side margins are rigidlysecured together, said sheets comprising a raised H-shaped rib disposedlongitudinally of the sheet in the middle thereof and decreasing indepth from the ridge towards the eaves with its ends merging into theplane of the sheet above the side plates thereof.

9. A car roof comprising roof sheets whose side margins are rigidlysecured together, each sheet comprising a substantially fiat-toppedraised H-shaped rib disposed lengthwise of the sheet near the middlethereof and being approximately one-half as wide as said sheet, theportions between the branches of the H being substantially fiat and ofuniform width and rising from the plane ofthe sheet at their eaves endsto the plane of the top of -the rib at their ridge ends.

GARTH G. GILPIN.

